envafolimab combined with chemotherapy in metastatic or recurrent gastric adenocarcinoma

Conditions: Metastatic or Recurrent Gastric Adenocarcinoma

Summary: the objective is to investigate the efficacy and safety of envafolimab combined with chemotherapy in the treatment of metastatic or recurrent gastric adenocarcinoma.

envafolimab indication: envafolimab is the world's first subcutaneous injection of pd-l1 monoclonal antibody.suitable for adult patients with advanced solid tumors with unresectable or metastatic microsatellite highly unstable (msi-h) or mismatch repair gene defects (dmmr).

Eligibility criteria:
inclusion criteria: * 18-75 years； * ecog 0-1； * life expectancy of at least 3 months； * negative for her2 gene expression by central laboratory ； * the tumor expresses pd-l1 as detected by the central laboratory, and the tumor proportion score (cps) ≥ 1； * at least one measurable objective tumor lesion by spiral ct examination, the maximum diameter ≥ 1cm（according to recist 1.1）； * diagnosed by histology and/or cytology, and assessed by imaging (refer to recist 1.1) as advanced metastatic gastric adenocarcinoma or gastric adenocarcinoma that has recurred after previous gastric cancer surgery; * not received systemic chemotherapy in the past. patients who have previously received fluorouracil monotherapy or fluorouracil-based adjuvant therapy or neoadjuvant therapy, and patients who have completed adjuvant therapy or neoadjuvant therapy before the start of the chemotherapy regimen in this trial 6 months ago can be included in this trial. in cases of metastatic disease requiring local remission, remission therapy with radiosensitizing doses of fluorouracil or capecitabine alone is permitted only ； * satisfactory main organ function，laboratory test must meet the following criteria: hemoglobin (hgb) ≥90g/l, neutrophil count（anc） ≥1.5×109/l, platelet count（plt） ≥80×109/l, serum creatinine（cr）≤1.5 upper normal limitation (unl)，total bilirubin (tbil) ≤1.5 upper normal limitation (unl), alanine aminotransferase (alt) and aspartate aminotransferase (ast) ≤2.5 unl (for patients with liver metastasis, the ast/alt must be ≤5.0 unl), activated partial thromboplastin time (aptt), international normalized ratio (inr), prothrombin time (pt) ≤ 1.5×uln; left ventricular ejection fraction (lvef) ≥ 50%; thyroid stimulating hormone (tsh) within the normal range within: if the baseline tsh exceeds the normal range, subjects with total t3 (or ft3) and ft4 within the normal range can also be enrolled; * subjects of childbearing potential must use an appropriate method of contraception during the study period and within 120 days after the end of the study, have a negative serum pregnancy test within 7 days prior to study enrollment, and must be non-lactating subjects ； exclusion criteria: * suffered from other malignant tumors within 5 years before the start of treatment in this study; * pathologically suggested patients with abnormally increased afp or msi-h ； * grade ≥1 unresolved toxicities (according to the most recent version of the national cancer institute \[nci\] common terminology criteria for adverse events \[ctcae\]) due to any prior therapy, excluding alopecia and fatigue; neurotoxicity was recovery to ≤ grade 1 or baseline before the group; * subjects with any severe and/or uncontrolled disease ； * poorly controlled diabetes (fasting blood glucose \[fbg\] \> 10 mmol/l) ； * received major surgical treatment, incisional biopsy, or significant traumatic injury within 28 days prior to the start of study treatment; or had a long-term unhealed wound or fracture； * serious arterial/venous thrombotic event within 6 months prior to initiation of study treatment ； * previously received drug therapy against pd-1, pd-l1 and other related immune checkpoints ； * participating in or participating in other clinical investigators within 4 weeks prior to the start of the study ； * allergic to the active ingredients or excipients of the study drug ； * unsuitable for the study or other chemotherapy determined by investigator.